Numerous methods and systems have been developed for conducting chemical, biochemical, and/or biological assays. These methods and systems are essential in a variety of applications including medical diagnostics, food and beverage testing, environmental monitoring, manufacturing quality control, drug discovery, and basic scientific research.
A variety of plate readers are available for conducting assay measurements in multi-well plates including readers that measure changes in optical absorbance, emission of luminescence (e.g., fluorescence, phosphorescence, chemiluminescence, and electrochemiluminescence), emission of radiation, changes in light scattering, and changes in a magnetic field. U.S. Patent Application Publications 2004/0022677 and 2005/0052646 of U.S. patent application Ser. Nos. 10/185,274 and 10/185,363, respectively, of Wohlstadter et al. describe solutions that are useful for carrying out singleplex and multiplex ECL assays in a multi-well plate format. They include plates that comprise a plate top with through-holes that form the walls of the wells and a plate bottom that is sealed against the plate top to form the bottom of the wells. The plate bottom has patterned conductive layers that provide the wells with electrode surfaces that act as both solid phase supports for binding reactions as well as electrodes for inducing electrochemiluminescence (ECL). The conductive layers may also include electrical contacts for applying electrical energy to the electrode surfaces.
Prior plate readers, including those capable of forming an image of luminescence generated in the plate wells, contain a detection mechanism that is an inseparable, integrated part of the plate reading apparatus. Repair of a component of the detection mechanism is, therefore, carried out in a piecemeal manner. In addition, a design or engineering change to one or more components of the apparatus that could function independently of the detection mechanism, such as a plate stacker, might require a consequent re-design of detection mechanism components physically associated with or otherwise impacted by such a changed apparatus component. Such alterations might lead to inconsistent performance within or across product lines despite their using the same basic detection components. Yet, detection systems serve a core function to all luminescence based readers, in contrast to those mechanisms that serve to receive the samples and deliver them into the system in any one of a number of formats (e.g., plates, cartridges, flow cells). Therefore, there is a need for a core detection module that can be manufactured, serviced, replaced, and integrated interchangeably into a variety of reading apparatuses as a self-contained sub-assembly.